Let's roll up our sleeves and solve this. We have 823 and we're going to multiply it by 12, essentially adding 823 to itself 12 times.
Step 1: 0 + 823 = 823
Step 2: 823 + 823 = 1646
Step 3: 1646 + 823 = 2469
Step 4: 2469 + 823 = 3292
Step 5: 3292 + 823 = 4115
Step 6: 4115 + 823 = 4938
Step 7: 4938 + 823 = 5761
Step 8: 5761 + 823 = 6584
Step 9: 6584 + 823 = 7407
Step 10: 7407 + 823 = 8230
Step 11: 8230 + 823 = 9053
Step 12: 9053 + 823 = 9876

So, 823*12 = 9876